ABSTRACT
Although osteophytes in climbers' fingers are known as part of a mechano‐adaption, the progression of osteophytes and contributing factors during an advanced elite climber's career is still unknown. This study analyzes osteophyte growth over 10 years for each phalangeal head and base of all proximal and distal interphalangeal joints (PIP and DIP) individually as well as the impact of potential climbing related influencing factors. Furthermore, the osteophytes located at the palmar neck of the proximal phalanx (palmar neck osteophytes) were investigated separately and joint space narrowing was evaluated and compared with osteophyte growth. Radiographs of 31 male elite climbers were analyzed in lateral view for osteophytes and in anterior–posterior (a.p.) view for joint space at baseline and 10‐year follow‐up. Even after more than 2 decades of elite climbing, osteophytes grew significantly at most phalangeal heads and bases. Already severely affected joints at baseline, specifically DIP Dig III and IV of both hands, had an especially high effect size (DIP base: Dig III: left; 0.517, right; 0.355, Dig IV: left; 0.519, right; 0.555, DIP head: Dig III: left; 0.348, right; 0.591, Dig IV: left; 0.533, right; 0.408). The extent of osteophytes at baseline is highly predictive for further development (79.3%); however, no climbing‐related factors were determinable for additional explanation. Palmar neck osteophytes are pathognomonic to climbing as they are most likely caused by the phalangeal base hitting this area repeatedly in a hyperflexed position. Furthermore, there is no correlation between osteophyte growth and joint space narrowing during an elite climber's career.
Keywords: climbing, osteophyte growth, palmar neck osteophyte
Highlights
Even after 20 years or more of high‐level climbing, a significant osteophyte growth over the last 10 years can be observed at almost all phalangeal heads and bases.
The extent of osteophytes at baseline is highly predictive for further development; however, no climbing related factor could be identified to explain the vast differences between the climbers.
Osteophytes located at the palmar neck of the proximal phalanx are pathognomonic to climbing as they are most likely caused by the phalangeal base hitting this area in an hyperflexed position.
1. Introduction
Since climbing keeps pushing the boundaries of difficulty ever further as well as attracting more and younger people than ever (Schweizer 2012), profound knowledge about its long‐term effects has become crucial. Climbing holds are often tiny, especially in advanced routes. Therefore, climbers are using multiple different special grip techniques, such as the “crimp position” (Bollen 1988), to maximize the range of motion in DIP (hyperextended) and PIP (hyperflexed) joints, leading to great mechanical stress on bone and tissue (Schweizer 2001; Schweizer and Hudek 2011). Hence, mechano‐adaption of soft tissue, such as hypertrophies of pulleys, palmar plates, cartilage, and flexor tendons (Fröhlich et al. 2021; Pastor et al. 2020; Pastor, Fröhlich, et al. 2022; Schreiber et al. 2015), is already a well‐known fact. Similarly, structural bone differences in fingers between high‐level climbers and nonclimbers are well investigated. Allenspach et al. and Pastor et al. found a significant greater cortical thickness as well as more frequent base osteophytes and signs of osteoarthritis in most DIP and PIP joints (Allenspach et al. 2011; Pastor, Fröhlich, et al. 2022). The focus of this study is to highlight the progression of osteophytes within male adult elite climbers (defined as having reached a climbing level of 7b + or above (French scale) as well as a minimum of 10 years of climbing experience at the time of baseline examination) over a period of 10 years.
Adaptive reactions (broadened joint base, subchondral sclerosis, and cortical hypertrophy) are solely in youth climbers dependent on training intensity and years climbing (V. Schoeffl et al. 2004). Additionally, it could be shown that total training years, campus board training during youth and climbing level at the 11‐year follow‐up were significant risk factors for early onset osteoarthritis (V. R. Schoeffl et al. 2018).
In addition to head and base osteophytes, some climbers develop palmar neck osteophytes on the palmar site of the proximal phalanges (Allenspach et al. 2011). However, no study has yet been found that analyzes them separately.
Previous studies have shown that elite climbers experience an overall decrease in cartilage thickness (while it still being greater than in nonclimbers) and an increase in the number of joints affected by clear signs of osteoarthritis over 10 years of further high‐level climbing (Pastor, Fröhlich, et al. 2022; Pastor, Fröhlich, et al. 2022). However, it is currently unknown whether joint space narrowing leads to an excessive osteophyte growth or vice versa.
Therefore, the aims of this study are (1) to analyze the osteophyte growth over 10 years for each joint (Dig II‐V, both hands, DIP, and PIP) separately for phalangeal head and base, (2) to assess potential risk factors for the growth of osteophytes in adults, (3) to analyze the palmar neck osteophytes as a separate entity and their progression over 10 years, and (4) to investigate joint space narrowing over the follow‐up period as well as the relationship between osteophyte growth and joint space narrowing.
2. Materials and Methods
2.1. Participants and Study Design
The participants of this study include 31 male high‐level climbers who were interviewed and examined twice (baseline, 10‐year follow‐up) with a 100% follow‐up rate (regarding the analysis of joint space narrowing, the follow‐up rate was 96.8% due to a missing x‐ray). All of them were still active climbers at the time of the follow‐up examination, had at least 25 years of climbing experience as well as no major hand‐injuries (i.e., finger fractures, ruptured tendons) or any hand‐surgeries. Anthropometrics are shown in Table 1.
TABLE 1.
Anthropometric details.
| Variable | Mean ± SD | Median | Range |
|---|---|---|---|
| Body weight at baseline [kg] | 71.6 ± 6.6 | 72.0 | 54.0–85.0 |
| BMI at baseline [kg/m2] | 22.6 ± 2.1 | 22.4 | 19.1–28.7 |
| a Years of climbing [y] | 32 ± 4.4 | 30.0 | 25–42 |
| a Age at climbing start [y] | 15.4 ± 3.3 | 15.0 | 6.0–24.0 |
| b Lifetime climbing/bouldering hours [h] | 25,798.1 ± 11,734.1 | 26,520.0 | 8320.0–54,080.0 |
| a Climbing level at 10‐year follow‐up (redpoint) | 9.8 (7c+) ± 3.5 | 10.0 (7c) | 1.0‐17.0 (6b–9a) |
| a Highest level in sport climbing (redpoint) | 13.7 (8b) ± 2.3 | 13.0 (8b) | 7.0‐18.0 (7b + ‐9a+) |
Data already presented in Pastor et al., the transformation from French scale difficulty to numerical scale (1 = 6b to 18 = 9a+) was retained (Pastor, Schweizer, Reissner, et al. 2022): For example, the level 6b in French scale was transformed to a 1, 6b + French scale to a 2, 7b+ = 8, and 9a+ = 18.
extrapolated hours a participant spent climbing or bouldering in his life based on reported weekly hours.
Only the climbers' a.p. and lateral x‐rays of both hands as well as the information retrieved from questionnaires at baseline (Allenspach et al. 2011; Hahn et al. 2012) and 10‐year follow‐up examinations (Pastor, Fröhlich, et al. 2022) were used.
The ethics committee approved this study (Kantonale Ethikkomission Zürich, BASEC‐Nr. 2019‐00677) and all participants gave written consent.
2.2. Data Collection and Evaluation
The osteophytes at the PIP and DIP joints' phalangeal head and base of both hand's Dig. II‐V were analyzed in lateral x‐rays using the grading system Allenspach et al. suggested. The phalangeal head osteophytes' grading depends on if and how much they are overhanging: Grade 1 was given for osteophytes with no overhanging part, grade 2 for osteophytes with an overhang (but not fulfilling the criteria for grade 3), and grade 3 are osteophytes whose overhanging part is larger than the gap between osteophyte and phalanx or broken osteophytes (Allenspach et al. 2011). An example is given in Figure 1.
FIGURE 1.
Grading system for phalangeal head and base osteophytes. The phalangeal head osteophyte of the left Dig III PIP is a grade 3 osteophyte, since the length of the overhanging part (red line) is larger than the distance from the phalanx (blue line). The phalangeal base osteophyte of the left Dig IV PIP has been assigned a grade 2, the center of rotation is marked with a circle.
The phalangeal base osteophytes are graded as follows: A first reference line runs from the joint's center of rotation through the middle of the next phalanx. Then 3 vertical lines were placed. For each line reached, a grade was added. One vertical line tangents the phalangeal head (marks the beginning of grade 1), one goes through the center of rotation (beginning of grade 3), and one is in the middle of them (beginning of grade 2). Grade 3 also includes broken osteophytes (Allenspach et al. 2011). In Figure 1, the grading of the base osteophyte of Dig IV PIP is illustrated.
The following variables were considered as risk factors to have severe head and/or base osteophyte findings at DIP and PIP joints of fingers II–V at the 10‐year follow‐up: total osteophytes score at baseline (see statistical analysis for further explanation), age at climbing start, lifetime training hours, total years climbing, highest reached climbing difficulty (redpoint), weight (at baseline), and BMI (at baseline).
The palmar neck osteophytes were evaluated in lateral x‐rays (baseline and follow‐up, Dig II‐V, PIP, and DIP joints, both hands) and graded using the following system: A first line is going from the center of the phalangeal head to the middle of the phalangeal base. Then, a parallel line is set as a tangent to the phalangeal head's most outer point. Finally, a third line was laid in the exact middle of the first two lines. Grade 1 is defined as not crossing the middle line, grade 2 is crossing the middle line but not the outer line, and grade 3 is crossing both lines (Figure 2).
FIGURE 2.
Grading system for palmar neck osteophytes. The palmar neck osteophyte is crossing the outermost line (line number 2) and therefore given grade 3.
For all lateral radiographs a custom‐made positioning device was used, which ensured the correct lateral finger position of Dig II–V. Consecutively, reproducible radiographs with a comparable quality as separately taken lateral x‐rays were achieved. This approach was favored against individual lateral radiographs to minimize radiation exposure to the young and healthy cohort as well as to keep costs and effort low.
Despite this standardized protocol, some x‐rays had to be excluded due to projection error as it was impossible to differ any potential palmar neck osteophytes.
Based on this study's calculation of phalangeal head and base osteophytes, the following joints were selected to assess joint space narrowing as well as a potential correlation between osteophyte growth and joint space width: the most affected joint at the 10‐year follow‐up examination, the joint with the most relative osteophyte growth from baseline as well as the joint least affected (baseline and 10‐year follow‐up). The joint space was measured in the middle of the joints in a.p. radiographs at baseline and 10‐year follow‐up. The osteophyte score was then adapted: The joint's higher score from either the phalangeal head or the phalangeal base osteophyte was used.
2.3. Statistical Analysis
Statistical analyses were conducted using IBM SPSS version 29 and Excel Microsoft 365.
Osteophyte growth was tested individually for each phalangeal head and base (DIP and PIP joints; Dig II‐V; and both hands) individually using the Wilcoxon‐test (one‐sided and p < 0.05). For every significant result, the effect size was calculated using the correlation coefficient r (thresholds: r = 0.1 for small, r = 0.25 for medium, and r = 0.4 for big). To assess the overall severity of head and base osteophytes for each climber, all his scores from baseline or 10‐year follow‐up, respectively, were added up to a total score with a maximum of 96 points (16 joints, head and base, and grade 0–3). Linear regression was used to evaluate the impact of risk factors on the total score at the 10‐year follow‐up examination (forward selection method, Pearson‐correlation between dependent and independent variable p < 0.05).
The occurrence of palmar neck osteophytes was described using relative frequencies.
Joint space width's change over the follow‐up period was evaluated with paired t‐test (two‐sided, p < 0.05).
The correlation between the absolute value of joint space width's change and osteophyte growth was tested with Spearman's correlation.
3. Results
3.1. Osteophyte Growth
Table 2 shows the absolute number of climbers (count (n)) as well as the relative frequencies (row valid N %) per grade for each individual phalangeal head and base osteophytes of the PIP and DIP joints Dig II–V at the baseline and 10‐year follow‐up examination: A general shift toward the higher grades after 10 years of further climbing can be observed.
TABLE 2.
Descriptive statistics for phalangeal‐head and base osteophytes.
| Grade 0 | Grade 1 | Grade 2 | Grade 3 | |||||
|---|---|---|---|---|---|---|---|---|
| Count (n) | Row valid N % | Count (n) | Row valid N % | Count (n) | Row valid N % | Count (n) | Row valid N % | |
| b DIP head le D2 | 29 | 93.5% | 0 | 0.0% | 2 | 6.5% | 0 | 0.0% |
| b DIP base le D2 | 15 | 48.4% | 15 | 48.4% | 1 | 3.2% | 0 | 0.0% |
| b PIP head le D2 | 27 | 87.1% | 4 | 12.9% | 0 | 0.0% | 0 | 0.0% |
| b PIP base le D2 | 29 | 93.5% | 1 | 3.2% | 0 | 0.0% | 1 | 3.2% |
| fu DIP head le D2 | 25 | 80.6% | 3 | 9.7% | 3 | 9.7% | 0 | 0.0% |
| fu DIP base le D2 | 11 | 35.5% | 18 | 58.1% | 0 | 0.0% | 2 | 6.5% |
| fu PIP head le D2 | 23 | 74.2% | 5 | 16.1% | 3 | 9.7% | 0 | 0.0% |
| fu PIP base le D2 | 25 | 80.6% | 4 | 12.9% | 0 | 0.0% | 2 | 6.5% |
| b DIP head le D3 | 22 | 71.0% | 3 | 9.7% | 5 | 16.1% | 1 | 3.2% |
| b DIP base le D3 | 12 | 38.7% | 14 | 45.2% | 3 | 9.7% | 2 | 6.5% |
| b PIP head le D3 | 16 | 51.6% | 8 | 25.8% | 3 | 9.7% | 4 | 12.9% |
| b PIP base le D3 | 21 | 67.7% | 9 | 29.0% | 0 | 0.0% | 1 | 3.2% |
| fu DIP head le D3 | 17 | 54.8% | 5 | 16.1% | 9 | 29.0% | 0 | 0.0% |
| fu DIP base le D3 | 8 | 25.8% | 13 | 41.9% | 4 | 12.9% | 6 | 19.4% |
| fu PIP head le D3 | 15 | 48.4% | 4 | 12.9% | 7 | 22.6% | 5 | 16.1% |
| fu PIP base le D3 | 16 | 51.6% | 12 | 38.7% | 1 | 3.2% | 2 | 6.5% |
| b DIP head le D4 | 29 | 93.5% | 0 | 0.0% | 1 | 3.2% | 1 | 3.2% |
| b DIP base le D4 | 15 | 48.4% | 11 | 35.5% | 3 | 9.7% | 2 | 6.5% |
| b PIP head le D4 | 24 | 77.4% | 4 | 12.9% | 1 | 3.2% | 2 | 6.5% |
| b PIP base le D4 | 21 | 67.7% | 7 | 22.6% | 1 | 3.2% | 2 | 6.5% |
| fu DIP head le D4 | 19 | 61.3% | 8 | 25.8% | 3 | 9.7% | 1 | 3.2% |
| fu DIP base le D4 | 3 | 9.7% | 17 | 54.8% | 7 | 22.6% | 4 | 12.9% |
| fu PIP head le D4 | 18 | 58.1% | 7 | 22.6% | 4 | 12.9% | 2 | 6.5% |
| fu PIP base le D4 | 17 | 54.8% | 9 | 29.0% | 1 | 3.2% | 4 | 12.9% |
| b DIP head le D5 | 29 | 93.5% | 2 | 6.5% | 0 | 0.0% | 0 | 0.0% |
| b DIP base le D5 | 19 | 61.3% | 11 | 35.5% | 1 | 3.2% | 0 | 0.0% |
| b PIP head le D5 | 30 | 96.8% | 1 | 3.2% | 0 | 0.0% | 0 | 0.0% |
| b PIP base le D5 | 29 | 93.5% | 2 | 6.5% | 0 | 0.0% | 0 | 0.0% |
| fu DIP head le D5 | 29 | 93.5% | 2 | 6.5% | 0 | 0.0% | 0 | 0.0% |
| fu DIP base le D5 | 8 | 25.8% | 22 | 71.0% | 1 | 3.2% | 0 | 0.0% |
| fu PIP head le D5 | 27 | 87.1% | 4 | 12.9% | 0 | 0.0% | 0 | 0.0% |
| fu PIP base le D5 | 27 | 87.1% | 4 | 12.9% | 0 | 0.0% | 0 | 0.0% |
| b DIP head ri D2 | 27 | 87.1% | 2 | 6.5% | 1 | 3.2% | 1 | 3.2% |
| b DIP base ri D2 | 15 | 48.4% | 13 | 41.9% | 1 | 3.2% | 2 | 6.5% |
| b PIP head ri D2 | 29 | 93.5% | 1 | 3.2% | 1 | 3.2% | 0 | 0.0% |
| b PIP base ri D2 | 29 | 93.5% | 1 | 3.2% | 0 | 0.0% | 1 | 3.2% |
| fu DIP head ri D2 | 23 | 74.2% | 4 | 12.9% | 4 | 12.9% | 0 | 0.0% |
| fu DIP base ri D2 | 12 | 38.7% | 12 | 38.7% | 3 | 9.7% | 4 | 12.9% |
| fu PIP head ri D2 | 25 | 80.6% | 4 | 12.9% | 2 | 6.5% | 0 | 0.0% |
| fu PIP base ri D2 | 25 | 80.6% | 5 | 16.1% | 0 | 0.0% | 1 | 3.2% |
| b DIP head ri D3 | 27 | 87.1% | 2 | 6.5% | 2 | 6.5% | 0 | 0.0% |
| b DIP base ri D3 | 11 | 35.5% | 15 | 48.4% | 2 | 6.5% | 3 | 9.7% |
| b PIP head ri D3 | 19 | 61.3% | 6 | 19.4% | 3 | 9.7% | 3 | 9.7% |
| b PIP base ri D3 | 23 | 74.2% | 4 | 12.9% | 3 | 9.7% | 1 | 3.2% |
| fu DIP head ri D3 | 17 | 54.8% | 8 | 25.8% | 5 | 16.1% | 1 | 3.2% |
| fu DIP base ri D3 | 9 | 29.0% | 13 | 41.9% | 3 | 9.7% | 6 | 19.4% |
| fu PIP head ri D3 | 17 | 54.8% | 5 | 16.1% | 6 | 19.4% | 3 | 9.7% |
| fu PIP base ri D3 | 19 | 61.3% | 8 | 25.8% | 0 | 0.0% | 4 | 12.9% |
| b DIP head ri D4 | 24 | 77.4% | 6 | 19.4% | 1 | 3.2% | 0 | 0.0% |
| b DIP base ri D4 | 10 | 32.3% | 15 | 48.4% | 3 | 9.7% | 3 | 9.7% |
| b PIP head ri D4 | 26 | 83.9% | 4 | 12.9% | 1 | 3.2% | 0 | 0.0% |
| b PIP base ri D4 | 24 | 77.4% | 3 | 9.7% | 0 | 0.0% | 4 | 12.9% |
| fu DIP head ri D4 | 20 | 64.5% | 6 | 19.4% | 5 | 16.1% | 0 | 0.0% |
| fu DIP base ri D4 | 3 | 9.7% | 16 | 51.6% | 5 | 16.1% | 7 | 22.6% |
| fu PIP head ri D4 | 22 | 71.0% | 7 | 22.6% | 1 | 3.2% | 1 | 3.2% |
| fu PIP base ri D4 | 21 | 67.7% | 6 | 19.4% | 1 | 3.2% | 3 | 9.7% |
| b DIP head ri D5 | 31 | 100.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| b DIP base ri D5 | 21 | 67.7% | 9 | 29.0% | 1 | 3.2% | 0 | 0.0% |
| b PIP head ri D5 | 31 | 100.0% | 0 | 0.0% | 0 | 0.0% | 0 | 0.0% |
| b PIP base ri D5 | 30 | 96.8% | 1 | 3.2% | 0 | 0.0% | 0 | 0.0% |
| fu DIP head ri D5 | 30 | 96.8% | 1 | 3.2% | 0 | 0.0% | 0 | 0.0% |
| fu DIP base ri D5 | 13 | 41.9% | 16 | 51.6% | 1 | 3.2% | 1 | 3.2% |
| fu PIP head ri D5 | 30 | 96.8% | 1 | 3.2% | 0 | 0.0% | 0 | 0.0% |
| fu PIP base ri D5 | 27 | 87.1% | 4 | 12.9% | 0 | 0.0% | 0 | 0.0% |
Abbreviations: b: baseline; fu: 10‐year follow‐up; DIP: distal interphalangeal joint; PIP: proximal interphalangeal joint; base: phalangeal base osteophyte; head: phalangeal head osteophyte; ri: right; le: left; D2; Dig II; D3: Dig III; D4: Dig IV; D5: Dig V.
There is significant osteophyte growth for at least one phalangeal head, respectively, base in every joint, except the PIP Dig III right, as shown in Table 3. A radiographic example for osteophyte growth is shown in Figure 3. At baseline examination as well as at the 10‐year follow‐up, all DIP joints had in average higher scores than the corresponding PIP except Dig III right (Pastor, Fröhlich, et al. 2022). Moreover, osteophytes at already severely affected joints at baseline grew significantly even though the climbing difficulty was sinking.
TABLE 3.
p‐values for each phalangeal head and base individually.
| p‐value (onesided)a | Dig5 le | Dig4 le | Dig3 le | Dig2 le | Dig3 ri | Dig4 ri | Dig5 ri | ||
|---|---|---|---|---|---|---|---|---|---|
| DIP | Base | 0.004** | 0.001** | 0.002** | 0.018* | 0.015* | 0.024* | 0.001** | 0.002** |
| Head | 0.500 | 0.002** | 0.027* | 0.030* | 0.065 | 0.001** | 0.012* | 0.159 | |
| PIP | Base | 0.079 | 0.065 | 0.023* | 0.030* | 0.023* | 0.054 | 0.159 | 0.042* |
| Head | 0.042* | 0.007** | 0.054 | 0.027* | 0.048* | 0.083 | 0.017* | 0.159 | |
Abbreviations: DIP: distal interphalangeal joint; PIP: proximal interphalangeal joint; base: phalangeal base osteophyte; head: phalangeal head osteophyte; ri: right; le: left; D2: Dig II; D3: Dig III; D4: Dig IV; D5: Dig V.
p < 0.05.
p < 0.01.
FIGURE 3.
Phalangeal head resp. base Osteophyte Growth. Lateral radiographs (right hand) of a high‐level climber at baseline (left) and 10‐year follow‐up (right). Especially remarkable is the phalangeal head osteophyte growth of Dig III, PIP. Lateral radiographs (right hand) of a high‐level climber at baseline (left) and 10‐year follow‐up (right). Especially remarkable is the phalangeal head osteophyte growth of Dig III, PIP.
The effect size for osteophyte growth in phalangeal heads and bases has two main tendencies: (1) it is greater in DIP than in PIP joints and (2) it is greater in Dig III‐V than Dig II. The highest effect size is at DIP Dig IV phalangeal base left and at DIP Dig III phalangeal head right with r = 0.591 each.
Table 3 shows the osteophyte growth's p‐value for each joint separated in phalangeal head and base; Table 4 presents the effect sizes for all significant p‐values (Table 5).
TABLE 4.
Effect size for all significant p‐values.
| Effect size | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Dig5 le | Dig4 le | Dig3 le | Dig2 le | Dig2 ri | Dig3 ri | Dig4 ri | Dig5 ri | ||
| DIP | Base | 0.476 b | 0.591 b | 0.517 b | 0.379 a | 0.392 a | 0.355 a | 0.555 a | 0.517 b |
| Head | 0.533 b | 0.348 a | 0.339 a | 0.591 b | 0.408 b | ||||
| PIP | Base | 0.358 a | 0.339 a | 0.358 a | 0.311 a | ||||
| Head | 0.311 a | 0.441 b | 0.348 a | 0.299 a | 0.381 a | ||||
Note: The effect size is only for significant p‐values (p < 0.05) calculated using correlation coefficient r.
*r > 0.1: small.
r > 0.25: medium.
r > 0.4 strong.
TABLE 5.
Pearson‐correlation for each risk factor with the total score at the 10‐year follow‐up.
| Variable | Pearson correlation | Sig. (2‐Tailed) |
|---|---|---|
| Total score at baseline | 0.895 a | 0.000 |
| Lifetime training hours | 0.283 | 0.124 |
| BMI | 0.164 | 0.377 |
| Years of climbing | 0.272 | 0.139 |
| Weight [kg] | 0.144 | 0.441 |
| Highest level climbing (redpoint) | 0.271 | 0.141 |
| Age at climbing start | 0.075 | 0.689 |
Correlation is significant at the 0.01 level (2‐tailed).
3.1.1. Contributing Factors
There was no significant Pearson‐correlation between the total score at the 10‐year follow‐up (dependent variable) and age at climbing start, lifetime training hours, total years climbing, highest reached climbing difficulty (redpoint), weight (at baseline) and BMI (at baseline), leaving the total score at baseline as the only significant independent variable (p < 0.001).
The linear regression model shows that the total score at baseline explains 79.3% (p < 0.001) of the total score 10 years later (with B = 1.171 and std. error of the estimate 5.720).
3.1.2. Palmar Neck Osteophytes
Since palmar neck osteophytes appear in a variety of shapes, Figure 4 is illustrating three examples. Palmar neck osteophytes were far less common in this study group than the phalangeal head and base osteophytes, and therefore, no statistical test was applied. However, looking at them individually, a growth can be observed (Figure 5).
FIGURE 4.
Three examples of different appearances of palmar neck osteophytes. Lateral radiographs of palmar neck osteophytes at the proximal phalanges. The palmar neck osteophyte on the left and middle radiograph is just about to develop, whereas the palmar neck osteophytes on the right radiograph has already grown together with the joint head.
FIGURE 5.
Growth of palmar neck osteophytes. Lateral radiographs (left hand) of a high‐level climber at baseline (left) and 10‐year follow‐up (right). Palmar neck osteophytes at phalanges 1 of Dig III and IV are already clearly visible at baseline and even more pronounced at the 10‐year follow‐up.
Eighteen of 31 climbers had at least one palmar neck osteophyte at the 10‐year follow‐up. Furthermore, 4 climbers had at least one joint which needed to be excluded due to projection error (in total 7 joints). From all valid results, 32 PIP joints had at baseline a palmar neck osteophyte versus 54 PIP joints at the follow‐up examination (increase of +68.75%); both PIP Dig II were hardly ever affected. No DIP joint fulfilled the criteria for palmar neck osteophytes.
The distribution among the most affected joints (both hand's PIP of Dig III and IV) is as follows:
Dig III PIP left and right together (total of 62 joints) had at baseline 47 joints with score 0 (relative frequency of 75.8%), 2 joints with score 1 (3.2%), 11 joints with score 2 (17.7%), and 2 joints with score 3 (3.2%). At the 10‐year follow‐up, the distribution was as follows: 37 joints with score 0 (60.7%), 7 joints with score 1 (11.5%), 11 joints with score 2 (18.0%), and 6 joints with score 3 (9.8%).
For Dig IV PIP for both hands at baseline: 49 joints with score 0 (79.0%), 4 joints with score 1 (6.5%), 9 joints with score 2 (14.6%), and 0 joints with score 3 (0%). At the 10‐year follow‐up: 42 joints with score 0 (67.7%), 10 joints with score 1 (16.1%), 7 joints with score 2 (11.3%), and 3 joints with score 3 (4.8%).
3.2. Joint Space Width and Osteophyte Growth
Based on the calculations of phalangeal head and base osteophytes the following 3 joint spaces were evaluated: Dig. III DIP left being the most affected at the 10‐year follow‐up, Dig IV DIP right being the joint with the most relative change from baseline, and Dig V PIP right being the joint least affected (baseline as well as 10‐year follow‐up). One climber was excluded because of a missing x‐ray.
The two‐sided paired t‐test was significant for all 3 joints (Dig III DIP left: p = 0.005 and Dig IV DIP right and Dig V PIP right: p = 0.001). Interestingly, 65 out of 90 joints had a wider joint space at the 10‐year follow‐up than at the baseline examination.
There was no significant Spearman‐correlation for any evaluated joint between the absolute value of joint space width's change and osteophyte growth.
4. Discussion
The main findings are as follows: (1) Osteophytes have grown significantly at almost all phalangeal heads and bases of DIP and PIP joints Dig II–V over the last 10 years; (2) the total score at baseline is a strong predictor for osteophyte severity 10 years later; (3) palmar neck osteophytes are characteristic to high‐level climbing; and (4) there is no correlation between osteophyte growth and change in joint space width.
4.1. Osteophyte Growth
This study showed significant osteophyte growth in almost all phalangeal heads and bases. Pastor et al. (Pastor, Fröhlich, et al. 2022) only found significant osteophyte growth in DIP left of fingers IV and V among the same climbers' radiographs. This different result is explained by a different statistic approach: Pastor et al. analyzed the osteophyte growth for each joint rather than for each phalangeal head and base separately. The results of this study show that osteophyte growth does not come to a halt, even after a long career and despite a falling climbing level.
This may indicate that osteophytes grow when physical stress above a so far undefined threshold is consistent. A follow‐up study with retired climbers would be necessary to support this thesis. In addition, the tendencies from previous studies that DIP joints are more affected than PIP joints and that Dig III and IV are especially prone to osteophytes (Allenspach et al. 2011; Pastor, Fröhlich, et al. 2022) are consistent with the observed growth: The effect sizes of DIP Dig III and IV of both hands are particularly great. This leads to the conclusion that mechanical stress remains the primary cause of osteophyte growth.
4.2. Contributing Factors
The total score at baseline is highly predictive for osteophyte growth. This shows that there are vast differences in stress reactions since climbers with little to no osteophytes at baseline did not catch up over 10 years. However, no climbing related factor could be determined for explaining these differences.
All our climbers needed the crimp position and other high stress positions to reach their individual difficulty level. To reach a higher level of difficulty, greater grip strength alone is not sufficient. Other factors, including mobility, balance and general upper body strength, are also necessary. This is suggesting that beyond a certain difficulty level a higher climbing level does not significantly contribute to more severe osteophyte findings. Although Fröhlich et al. found that in these elite climbers weight and the highest level of difficulty achieved are significant factors for part of the soft tissue adaption (palmar plate thickness) (Fröhlich et al. 2021), it could not be adopted for osteophyte growth.
Before this study was conducted, we hypothesized that the age at which climbing starts may have a significant impact on the development of osteophytes since growing bones react differently than adult ones. Schöffl et al. showed that although elite youth climbers do have adaptive osteological reactions (broadened joint space, subchondral sclerosis, and cortical hypertrophy), osteophytes are not present (V. Schoeffl et al. 2004). At the 11‐year follow‐up, only few climbers developed osteophytes (V. R. Schoeffl et al. 2018). Nevertheless, these findings were not applicable to the climbers in this study, and it seems that starting to climb at a young age does not prevent or stimulate osteophyte growth later in career.
In those youth climbers with much less cumulative training in their life than the climbers of the current study, training intensity as well as bodyweight at baseline were significant predictors for developing radiographic stress reactions 11 years later. Moreover, overall total training years, campus board training at baseline and climbing level at follow‐up were significant risk factors for early onset osteoarthritis (V. R. Schoeffl et al. 2018). However, according to the current study, those effects appear to vanish in a later elite career.
All these results suggest that although climbing related factors are essential to the development and growth of osteophytes, there must be other nonrelated contributing factors, which likely are genetics. A study found osteophytes to be the most heritable feature of osteoarthritis. The heritability of osteophytes in DIP and PIP joints was 36% resp. 30% which is lower than that of osteophytes in the thumb, but still significant. In combination with the thumb not only the numbers of affected joints were significant but also the severity (Ishimori et al. 2010). There is a good possibility that the climbers with more severe findings have a genetic predisposition.
It is important to notice that our study group is very homogeneous with only male athletes and all of them having several decades of high‐level climbing training. Therefore, this result cannot be applied to the whole climbing community without restriction. Research on female climbers, a comparison with this male cohort as well as between right‐ and left‐handed people are necessary to gain knowledge over a broader part of the climbing community. Furthermore, the impact of ring ligament injuries as a minor but common injury on osteophyte growth could be evaluated.
4.3. Palmar Neck Osteophytes
It is widely accepted that osteophytes at the joint margins are an attempt to stabilise and cope with damaged joints (Coaccioli et al. 2022). Allenspach et al. described already the occurrence of osteophytes at the palmar neck just below the joint head (Allenspach et al. 2011). These osteophytes crucially differ from the ones at the phalangeal head or base in two points: Form and location. They do not resemble the typical overhanging spurs that are commonly found at the phalangeal head or base of DIP and PIP joints. Instead, they have a triangular to half‐circle shape and seem to be glued to the phalangeal neck. Therefore, this type of osteophyte questions whether the general theory of osteophytes is applicable for them or not. Nonetheless, no study could be found which analyses them as an own entity. Their location suggests that they form because of the phalangeal base hitting repeatedly this area in a hyperflexed position (e.g., in crimp position). Figure 6 illustrates this pathomechanism. Despite those fundamental differences, they also do not correlate with pain. Since no other activity reaches the same level of repetitive impact to this area of the body and having a lack of literature, we suggest these findings to be pathognomonic (even if not pathologic) to climbing respectively bouldering.
FIGURE 6.
Mechanism of osteophyte growth by collision during crimp. Drawing of a finger's (Dig II–V) phalanges in both flexion and extension. In (hyper‐)flexed position, the middle phalanx is hitting the typical area for palmar neck osteophytes at PIP joints.
4.4. Osteophyte Growth and Joint Space Narrowing
Pastor et al. found in their sonography‐based follow‐up study with the same climbers a significant decrease in cartilage thickness over 10 years (Pastor, Fröhlich, et al. 2022). However, in the current x‐ray‐based study, many climbers had a wider joint space at the 10‐year follow‐up examination than at the baseline. No explanation could be found since radiographic joint space width is considered highly correlating with sonographic assessed cartilage thickness (Mandl et al. 2015).
Joint space narrowing as well as osteophyte growth are both signs of osteoarthritis (Kellgren and Lawrence 1957), and are therefore driven by the same factors and often occur simultaneously (Pastor, Fröhlich, et al. 2022).
Therefore, an additional aim was to investigate whether extensive findings of one criterion led to a consecutive great expression of the other criterion. As previously stated, there was no correlation between the absolute change in joint space width as a surrogate for cartilage remodeling and osteophyte growth over 10 years. However, there are a few things which must be considered: Joint space widening (greater cartilage thickness) appears in mechano‐adaption/early osteoarthritis whereas joint space narrowing does not appear until more advanced stages, which requires a turnover at the maximum thickness (Pastor, Fröhlich, et al. 2022). With only two measurement points available, there is a risk of missed turning points, which would result in much greater change in joint space width.
Secondly, since the joint space width measurements do differ from the sonographic assessments of the cartilage thickness, it is open to what extent the joint space width represents the cartilage thickness in this study.
Thirdly, the climbers already had at least 10 years of high level climbing experience at baseline examination and adaptive reactions including a greater cartilage thickness than age matched controls (Pastor et al. 2020) and osteophytes (Hahn et al. 2012). With no data prior to the climbing career available, the whole extent of joint space width change could not be determined (it can though be assumed that no osteophytes existed before career start), leaving the question open if those two factors do correlate over one's whole climbing career. Further research especially including more data points regarding joint space width is needed to answer this question conclusively.
5. Conclusion
Even after 20 years or more of high‐level climbing, a significant osteophyte growth over the last 10 years can be observed at almost all phalangeal ends. Regarding the contributing factors of this growth, the extent of osteophytes at baseline are highly predictive. However, no climbing related factor could be identified to explain the vast differences between the climbers. Palmar neck osteophytes are pathognomonic to climbing and likely have a different etiology than the phalangeal end osteophytes, which is why it is important to consider them as an own entity. Changes in joint space width are significant; however, they do not correlate with osteophyte growth during an elite climber's career.
Funding
The authors received no specific funding for this work.
Ethics Statement
The ethics committee approved this study (Kantonale Ethikkomission Zürich, BASEC‐Nr. 2019‐00677) and all participants gave written consent.
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgments
The authors have nothing to report. Open access publishing facilitated by Universitat Zurich, as part of the Wiley ‐ Universitat Zurich agreement via the Consortium Of Swiss Academic Libraries.
Schmid, Priska , Fröhlich Stefan, Pastor Torsten, Reissner Lisa, and Schweizer Andreas. 2026. “Osteophyte Growth Over 10 Years in the Fingers of High‐Level Climbers and Contributing Factors,” European Journal of Sport Science: e70108. 10.1002/ejsc.70108.
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