Comparison of Advantage/Disadvantages, Recap & Pitfalls

1. Review of:
Lengthening of Fourth Brachymetatarsia
Three Different Surgical Techniques
By Chris Lim

2. RECAP

3. Recap
Purpose: Assess the clinical results of lengthening the fourth
metatarsal in brachymetatarsia using three different surgical
techniques
Hypothesis: Unclear/Not Stated
Retrospective Study
153 feet, 106 pts ( 100 female, 6 males)
Mean age: 26.3 years (13-48)

4. Recap
Group 1: One-Stage Intercalary bone graft, secured by an IM K-Wire
(45 feet, 35 pts)
Group 2: Gradual lengthening with a Mini-External Fixator after
performing an Osteotomy with a saw (59 feet, 39 pts)
Group 3: Gradual lengthening using a Mini-external Fixator after an
Osteotomy with an Osteotome (49 feet, 32 pts)

5. RESULTS

6. Results
Table I: Details of patients in each group
• Note: “n” (sample size) is based on number of people
• Mean age in years proved significance in all three groups, based on p-value
• Patients with bilaterality did not prove significance.
• Number of females did not prove significance based on p-value
May be acceptable due to the epidemiology behind Brachymetatarsia
Brachymetatarsia is more common in females
Female:Male ratio is 25:1

7. Results
Table II: Pre-Operative Variables
 Pre-op Percentage of the length of 4th metatarsal to the 2nd metatarsal - proved
significant
 Pre-op Shortness of 4th toe - proved significant
 Note: “n” (sample size) is based on number of feet

8. Results
Table III: Post-Operative Variables
Length gain for all three groups proved significance based on p-value
Length gain (%) was insignificant based on p-value
Percentage increase= lengthening obtained/ pre-operative length
Healing Index (wks/cm) was insignificant based on p-value
Fixation time for all three groups proved significance based on p-value
Note: 8 participants were disregarded due to failure of bone formation

9. Results
Table IV: Post-Operative Variables, based on AOFAS Score
AOFAS Score was insignificant based on p-value
Could be due to variance in pain tolerance levels in patients
AOFAS is based on Pain, Function, and Alignment
Subject Satisfaction score and Willingness was statistically significant
Note: All patients were considered for this data collection

10. Results – Pitfalls
Retrospective Study
Less control of variables
Sampling Bias
Hypothesis: Not stated
Mean age of pts: 26.3 years (Ranging from 13 to 48 years old)
Large range can lead to discrepancies in results of study (e.g., satisfaction survey and
overall healing time)

11. Results – Pitfalls
Study was not randomized
Selection bias
Patients were offered a choice of which treatment they wanted to
undergo
Researcher bias
Patient’s choice in treatment “may have been influenced by the
surgeon towards one-stage for pts with less shortening”

12. Results – Pitfalls
Sample size, “n,” was not consistent between the 4 tables
In Table 1, “n” represented number of patients
In Tables 2, 3, and 4, “n” represented number of feet
8 patients were disregarded in data collection post-operatively.
However, in the Table 4, which compared both pre-op and post-op
satisfaction and willingness to return, the 8 patients were taken
into consideration
Selection Bias

13. Results – Pitfalls
Discrepancy in metatarsal lengths between the groups
The preoperative length and length gain of the fourth metatarsal in the bone-graft
group were less short than those of the patients in other groups.
Technique of osteotomy in gradual lengthening was changed after
accumulating experience in the saw group
Leading to inconsistency
Compromises internal validity
Harmed patients prior to change in procedure

14. Results – Pitfalls
The pre-operative AOFAS score was 100 in all patients, and it was
reduced after surgery.
The main cause was pain at the plantar aspect of the proximal phalanx or
at the metatarsophalangeal joint after prolonged standing or walking and
decreased movement of this joint.
Despite this, the Willingness score was high (favorable)
Inconsistency in data

15. Results – Pitfalls
Mean Follow-Up: 22 months - ranging from 7 months to 55
months
Non-similar base-line measurements (range is too large)
AOFAS, Satisfaction score, and Willingness may have been affected
Recall bias may have occurs

16. DISCUSSION Section

17. Discussion
One-Stage Lengthening: Advantages
Advantages of One Stage Lengthening
Non requirement for a external fixator
No possibility of insufficient bone formation
No necessity for manipulation of the external fixator after
surgery

18. Discussion
One-Stage Lengthening: Disadvantages
Disadvantages of One Stage Lengthening
Limited lengthening
Immobilization of the MPJ during consolidation of the graft
Necessity for harvesting a bone graft
Allograft may lack capacity to heal
Maceration (most common problem of the plantar aspect of the MPJ, Due
to plantar slope of the met, the 4th toe is immobilized in a plantar-flexed
position promoting maceration)

19. Discussion
Gradual Lengthening – Advantages
Advantages of Gradual Lengthening
Ability to obtain greater length than one-stage
intercalary bone graft
Immediate weight-bearing can occur
Preservation of movement of the MPJ
Bone Osteotome reduces soft tissue damage

20. Discussion
Gradual Lengthening – Disadvantages
Disadvantage of Gradual Lengthening
Regular adjustment of the external fixator
Possibility of insufficient bone formation
Risk of pin-track infection
Micro-Saw method may cause local heat damage & necrosis

21. Micro-Saw

22. Non-specific to Surgical Tools
The Type and Model of the equipment used may cause
variance to the results.
Compromise the External Validity in achieving the same
results if the surgical techniques were repeated in a different
location.
Eg. Osteotome used in the Osteotomy was not specified.

23. Classic Osteotome

24. Bone Scapel Osteotome
https://www.youtube.com/watch?v=EnODsIhHUVI

25. Discussion
In the conclusion, the gradual lengthening method was re-stated as being the
most reliable.
However, in the Discussion section, only general references were made as to
the basic advantages of the method, which were not specific to the study.
Author explained many limitations:
Retrospective study
Selection bias for preferred lengthening by surgeon may have occurred
Technique in osteotomy was changed after accumulating experience in the saw group

26. Discussion – Pitfalls
Actual results were not discussed in this section
The Discussion section did not clearly match the Introduction in
comparing and concluding the most reliable result.
Overall, without a hypothesis, it is hard to compare the purpose of
the study with their conclusion.

27. CONCLUSION

28. Conclusion
In conclusion, the gradual lengthening by distraction osteogenesis
after osteotomy using an osteotome produces the most reliable
results for the treatment of fourth brachymetatarsia.

29. Conclusion – Pitfalls
Previously, research question was not clearly stated.
Hypothesis and null hypothesis was not stated.
Therefore, p-value credibility comes into question
p-value indicates whether or not there strong evidence against the null
hypothesis
Function of the p-value is to determine whether or not to reject the null
hypothesis
In this case, there is no hypothesis/null hypothesis to retain or reject

30. Conclusion – Pitfalls
Internal Validity was hindered due to multiple biases (as previously
mentioned)
External Validity
Tools and types of materials were not clearly stated
Study took place in Korea
Cultural differences may naturally occur
“distress felt by affected patients tends to be greater in Asian countries, where the feet are often
displayed indoors”
This may have skewed Satisfaction and Willingness survey

31. SUMMARY

32. Summary
 Future studies should be performed to overcome limitations due to:
 Biases (Recall bias, Selection biases, and Researcher bias)
 Prospective study would result in less confounding variables
 Could not be generalized to all clinical settings
 Some aspects of this study can be used for informative purposes, pre-operational
counseling, etc.
 Ex. More rapid healing time in bone graft, longer lengthening in the distraction method,
higher satisfaction scores with the gradual distraction with osteotome
 Overall, without a hypothesis and without clear evidence supporting this study’s
findings, it is hard to find this paper to be reliable

33. Resources
 Baek, G., & Chung, M. (1998). The treatment of congenital brachymetatarsia by one-stage lengthening. The
Journal Of Bone And Joint Surgery, 1040-1044.
 Choi, I., Chung, M., Baek, G., Cho, T., & Chung, C. (n.d.). Metatarsal Lengthening in Congenital
Brachymetatarsia: One-Stage Lengthening Versus Lengthening by Callotasis. Journal of Pediatric
Orthopaedics, 660-660.
 Ferrandez, L., Yubero, J., Usabiaga, J., & Ramos, L. (1993). Congenital Brachymetatarsia: Three Cases. Foot &
Ankle International, 529-533.
 Pasternack, W. (n.d.). Brachymetatarsia. A unique surgical approach. Journal of the American Podiatric
Medical Association, 415-418
.

34. Thank you